No, SSDs are not absolutely necessary for VDI storage. The general problem with most VDI implementation projects is the total cost of ownership (TCO) to make the virtual desktop performance adequate for the users. The biggest item in that TCO is the storage.
To get adequate storage performance requires either a lot of hybrid hard disk drives (HDDs), short stroked HDDs (throws away a lot of capacity) or SSDs. SSDs are quite effective in minimizing capacity requirements and reducing VDI TCO. Depending on the VDI implementation variation (PCIe SSD in the server, SSD caching appliance, 100% SSD storage system and hybrid storage), they can also be quite cost-effective.
They're not the only options available that drastically improve VDI storage performance and reduce VDI HDD or SSD requirements. There are software VDI accelerators from Atlantis Computing, Sanbolic and Virsto. These software options have been able to increase VDI storage performance enough to reduce capacity requirements by as much as 90% while reducing I/O latency and response time.
There is a way to calculate whether an SSD investment in implementing VDI is worthwhile, and it is completely subjective. First, determine the VDI performance requirements. Then establish which SSD implementation and at what cost will meet those requirements. Subtract out the cost savings from reduced HDDs, power, cooling, infrastructure, etc. Weigh performance, growth and user satisfaction versus TCO. Make a decision.
This was first published in December 2012